1992 Statistics

Production capacity was increased to 142,000 tons per day by the addition of a fourth grinding unit at Copperton, and continued use of the Bonneville/Magna "North Concentrator Complex."

Loading

Primary production utilizes the following number and type of units:

Quantity

Description

2

15-yd P&H 2100 electric power shovels

4

27-yd P&H 2800 Mark II electric power shovels

3

30-yd P&H 2800 XP electric power shovels

2

34-yd P&H 2800 XPA electric power shovels

The 15-yd shovels were used primarily for ore reload into trains, narrow cuts, and construction cuts. The larger shovels were used exclusively for waste and ore production faces.

The availability for the 2100 shovels averages 78 percent while that of the larger shovels averages 88 percent. The smaller shovels were scheduled 2 to 3 shifts/day and shovels larger than 15-yd were scheduled 14 to 15 shifts/day. Average productivity for the 2100 is 10,000 tons; for the Mark Il and 2800 XP, 15,000 tons, and for the 2800 XPA, 20,000 tons per shovel shift.

Power is provided by 44-kva distribution lines circling the pit. At appropriate points power is fed to 13.8-kva substations. Radial lines were then fed through smaller substations where the voltage is reduced to 5500 V ac to power shovels and drills. Electrical connections between the switch houses and shovels were made using trailing cables up to 2000 feet long for shovels and 3000 feet long for drills. However, cables have been run as long as 5000 to 6000 feet.

In addition to the main production fleet, two 8-yd International, one 12-yd Clark, and two 12-yd Caterpillar rubber-tired front end loaders were used for construction, clean-up, reload, and auxiliary production when needed.

Haulage

Originally, the mine was entirely rail haulage. Steam engines gradually were replaced by trolley locomotives, which, in turn, were replaced by diesel locomotives. Truck haulage was introduced in 1963. and by 1983, all primary production was accomplished by trucks. Rail reload operations were a vestige of the original haulage system and will continue to supplement ore production as long as they were profitable. In 1989, the rail haulage system accounted for approximately 30 percent of the ore production. The majority of the ore is hauled by truck to an in-pit crusher and transported to the mill by belt conveyor.

Rail reload utilizes 15-yd shovels and 12-yd loaders to fill 100-ton rail cars. Each 25-car train is powered by two 135-ton diesel locomotives. The total rail fleet consists of 11 locomotives and 500 ore cars. Ore is currently being transported approximately 12 miles to the Bonneville facility for crushing and processing.

Truck haulage utilizes a fleet of 44 trucks. This fleet is composed of:

Quantity

Description

28

190-ton Caterpillar mechanical-drive trucks

8

170-ton Unit Rig diesel-electric trucks

8

170-ton Wabco diesel-electric trucks

At the 1990 production level, approximately 34 truck-shifts/shift were scheduled, with an average availability of 94 percent for the new, larger trucks and 84 percent for the older, smaller trucks. All trucks were equipped with two-way mobile radios, which assist appropriate dispatching.

The in-pit, movable, 60- by 109-inch, 1000-hp Allis-Chalmers gyratory crusher can accommodate 120,000 tons per day on a continuous basis. The crusher can handle two trucks at a time and a dumping rate of one truck per minute. This rate is achievable only for short periods when the rock is highly fragmented. This facility is situated on the 5490 level, which is centrally located with respect to planned ore production over the next eight years. The entirely self-supporting crusher assembly is 100 ft high (from the truck dump ramp on the 5590 level to conveyor discharge on the 5490 level). Currently, it is resting on a 4200-yd concrete foundation. The crusher will be relocated using a 2000-ton crawler transporter. Three to four weeks will be required from the time a move begins until the crusher is brought back on-line at its new location.

Material processed through the facility is crushed to 10 inches and less size, and fed directly to the first flight of a six-segment 72-inch belt. The belt system is 5 miles long and capable of 10,000 tons per hour at a speed of 900 feet per minute.

After the ore is processed at the Copperton concentrator, the copper concentrate is pumped through a 6-inch diameter pipeline 17 miles to the smelter. The tails also were pumped through a 48-inch diameter pipeline 12 miles to the tailings pond near Magna.